Linux console is disabled in maemo stock kernel, if you wanna boot into console, you need to recompile maemo kernel and enable console.

I'm trying to boot into X in this debian, but OTOH having problems with the N900 rebooting once in it, due to watchdog resetting the device.

When you booted it, albeit without console output, and ssh'd in, did it stay on without rebooting?

How did you set-up watchdog, so it wouldn't reboot? I'm not having success using the tarball and instructions at elextravox's site...